Ecological context shapes the interpretation of biodiversity intactness metrics

Mean Species Abundance (MSA) is positively associated with local species richness and ecosystem productivity across 7,064 forest fragments worldwide, but these links weaken, disappear, or reverse by biome and taxonomic group.

• Why it matters: MSA relies on generalized pressure-impact relationships, so transferring it across regions or comparing decisions can misrepresent biodiversity intactness when ecological context differs.
• What they did: Using data from 7,064 forest fragments with 21,761 species across 11 biomes, the study tested how MSA relates to local/regional richness and ecosystem productivity, and whether relationships vary by vegetation condition, landscape structure, biome, and taxonomic group.
• The result: The MSA–productivity association held in only five of 11 biomes, while the MSA–regional richness association was negative in temperate conifer and boreal forests but positive in four other biomes, guiding when context or complementary data are needed.